Laplace integral transform inversion of rational proper fractions is the key to solve the differential and integral equation by Laplace transform.According to the classification of roots where the denominator of a rational proper fraction equals zero,we decompose a general rational proper fraction into the form of a partial fraction.Based on the partial fraction,we use the linear theorem of Laplace integral transformation to invert the rational proper fraction,and give the concrete form of the original function of the general rational proper fraction.The original functions corresponding to the...